<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="allNumber"/>
    </label>
    <span> <span>已完成{{successNum}}</span> / 全部 {{todoList.length}} </span>
    <button class="btn btn-danger" @click="deleteSuccess">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: "Footer",
  props:["todoList" , "allChangeHandle" , "deleteSuccess"],

  computed:{
    //计算已完成的数量
    successNum(){
      return this.todoList.reduce((p , c) => c.done ? p + 1 : p , 0) 
    },

    //计算总数量
    allNumber:{
      set(value){
        this.allChangeHandle(value)
      },
      get(){
        return this.todoList.every((item) => item.done) && this.todoList.length!==0
      }
    }

  },


};
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>